Liquid crystal display panels have a disadvantage of light leakage in a dark state, which results from phase delay occurring on glass substrates, due to external forces applied by periphery frames of display panels on upper and lower glass substrates, and an amplification effect on phase delay by liquid crystal in the display panels.
The specific reasons for light leakage in a dark state are as follows. Glass substrates are subjected to packaging forces of module frames, and stresses are generated in the glass substrates. In a case of no stress, the glass substrates are isotropic and phase delay does not occur on light transmitted through the glass substrates, and in a case where stresses are generated in the glass substrates, the glass substrates allow phase delay to occur on light transmitted therethrough. When displaying in a dart state, light transmission rate will be increased due to phase delay of lights allowed by the glass substrates and the amplification effect on phase delay by liquid crystal in the display panels, thereby increasing light leakage in a dark state.
The conventional method for solving the problem of light leakage in a dark state caused by the phase delays of the glass substrates is to arrange compensation films on the glass substrates. However, since periphery areas of display panels are subjected to external forces having different directions and sizes, phase delay of periphery areas of the glass substrates are also different. Therefore, the conventional compensation films, of which the optical axes have a fixed direction, cannot compensate phase delays of different areas of the glass substrates.